• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.12
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• pp.1071-1077
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• 2002

Ice adhesion on cooling wall is very important in continuous ice formation. The purpose of the present study is to investigate the possibilities of a three-component aqueous solution as a thermal storage material for the continuous ice formation. By freezing under stirring the solution of 300 mL in a stainless steel vessel which was immersed and cooled in a temperature controlled bath, an ice slurry was formed experimentally with measuring the temperature and stirring load variation. From the experiment, the ice adhesion was suppressed when the supercooling degree decreased and the concentration of aqueous solution increased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.8
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• pp.720-727
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• 2004

In the process of ice-slurry making, the phenomenon of ice adhesion influences extremely to ice making system. In this study, the effect on the ice adhesion by thermal storage material with additives is investigated quantitatively. Various solutions of 300 g in a stainless vessel were frozen under stirring. Through the experiment the ice adhesion between cooling wall and ice-slurry was compared with each other by measuring the stirring power. From the experiment, the stirring power in EG, SCA solution was smaller than those in the solution containing functional materials, such as poly-vinyl-alcohol or kitchen detergent.

• Journal of the Korean GEO-environmental Society
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• v.17 no.12
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• pp.45-54
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• 2016

In this study, the construction method of new underground continuos impervious wall that the bentonite slurry keeps the stability of excavated trench and the mixture of cement and bentonite plays a role as a constituent of impervious wall in the trench. The merit of homogeneity of the method so called as a cement-bentonite slurry wall enables to accurately make an estimation of hydraulic conductivity of the walls compared with that by other general grouting methods and to verify their waterproof efficiency without difficulty at the design stage. The use of cement-bentonite slurry walls for the containment of groundwater flow has also proven a cost-effective impervious wall technology by employing the simple combination of construction equipments and easy and fast construction procedures. The engineering characteristics of cement-bentonite impervious wall obtained by carrying out the laboratory experiments under various conditions. This study reveals the effect of variation of constituent materials and their mixing methods (Water-Cement-Bentonite) on the engineering characteristics of a composition. Also, this study makes some recommendations on the optimum mixing ratio and mixing sequence for the best quality at the site. That is the most important factors to estimate the construction cost and design of the technique. The comparison is lastly made to evaluate the effect of ordinary Portland and blast furnace slag cement as a bonding material on the behavior of impervious walls.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1264-1273
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• 2010

Soil-bentonite cutoff walls are widely recognized to be the effective barrier for containment of wastes and groundwater. Bentonite cake is usually found remaining on the trench surface due to the use of bentonite slurry during the excavation for the cutoff wall construction. Defects also inevitably take place due to the inappropriate construction procedures or improperly mixed soil-bentonite backfill. The defects include insufficient keys and windows in the soilbentonite cutoff wall. In this study, the performance of the soil-bentonite cutoff wall is evaluated based on the flow rates through the wall. Three-dimensional numerical models were applied to simulate the groundwater flow through the soil-bentonite cutoff walls of typical geometries with consideration of the defects and bentonite cake. Results of the simulations showed that the bentonite cake has no effect in the insufficient key cases. In the keyed wall cases, the bentonite cake with very low hydraulic conductivity significantly impedes the flow of groundwater through the wall. The presence of the bentonite cake not only compromises the window defect but also renders the wall construction more effective in blocking the groundwater flow. These findings show the significance of the bentonite cake in a soil-bentonite cutoff wall construction.

• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.53-66
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• 2023

In this study, the results of the elasto-plastic beam analysis, finite element analysis and optimization design of the steel pipe sheet pile applied as an earth retaining wall under the deep excavation were presented. Through this study, it was found that the high-strength and sea resistant steel pipe has high allowable stress, excellent structural properties, favorable corrosion, and high utilization as an earth retaining wall, and the C-Y type joint has significantly improved the tensile strength and stiffness compared to the traditional P-P type. In addition, it was investigated that even if the leak or defect of the wall occurs during construction, it has the advantage of being able to be repaired reliably through welding and overlapping. In the case of steel pipe wall, they were evaluated as the best in views of the deep excavation due to the large allowable bending stress and deformation flexibility for the same horizontal displacement than CIP or slurry wall. Elasto-plastic and finite element analysis were conducted in consideration of ground excavation under large-scale earth pressure (uneven pressure), and the results were compared with each other. Quantitative maximum value were found to be similar between the two methods for each item, such as excavation behavior, wall displacement, or member force, and both analysis method were found to be applicable in design for steel pipe sheet pile wall. Finally, it was found that economical design was possible when determining the thinnest filling method with concrete rather than the thickest hollow shape in the same diameter, and the depth (the embedded length through normality evaluation) without rapidly change in displacement and member force.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.653-660
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• 2008

The purpose of this study is to analyze the optimal mix design of the sound absorption material that is made from perlite and various binder systems for noise barrier wall. The polymer cement slurry which is made from two types of polymer dispersions, and silicone type inorganic material are used as binder. The test specimens are prepared with various polymer cement ratios, binder ratios, and tested for strengths, freezing and thawing and sound absorption performance by the tube and the reverberation room methods. From the test results, the difference of sound absorption coefficient by the tube method is a little recognized, however, noise reduction coefficient (NRC) of test specimens bound by the polymer cement slurry is in the ranges of 0.48 to 0.51. They are a little higher than those bound by cement only, and are lower values than recommended value of 0.7 by the Ministry of Environment. However, the sound absorption coefficient of test specimens at low frequency range of 250 to 500 Hz by reverberation room method shows very high values as 0.84 to 1.00, and 0.57 to 0.77 at the high frequency. The test specimens with polymer cement slurry binder have a good balance between performance and cost, and have proper properties in strengths, freezing and thawing resistance as sound absorption material for noise barrier wall. It is apparent that the good sound absorption material can be produced according to the optimum mix design that is recommended from this study.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.46-55
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• 2006

There are many kinds of braced cut wall methods as the sheet pile, SCW, CIP and slurry wall which is adoptable for a deep excavation construction in a coastal filled land. The braced cut wall which has a strong stiffness is very stable but it has the weak point that the construction cost is high. Thus when a braced cut wall is designed, the geotechnical engineers choose the braced cut wall which has more safe and economic in the consideration of surrounding buildings near the construction site. Especially, when the sheet pile method as a braced cut wall is cheesed, the layer order and consistence of a coastal deposit stratum are considered and the pile driving method is also considered. This paper introduces the case that the originally box-type sheet pile wall was changed to U-type and high strength material after the pilot test at the subway construction site in a coastal filled land. This paper also introduces the case that the sheet pile's driving method was changed to special method in the section of the temporary coffer dam which had made when the present coastal filled land was formed.

• Journal of Soil and Groundwater Environment
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• v.6 no.2
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• pp.57-67
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• 2001

The purpose of this study is to predict appropriate leachate rates and leachate transport velocity through weathered zone and basement rock on the transient condition at Nanji waste landfill. The leachate transport in the Nanji waste landfill is analyzed using MODFLOW(A Modular 3-D Finite Different Groundwater Flow Model) model which simulates three dimension groundwater flow and MT3D(A Modular Three Dimentional Transport Model) model which describes three dimensional transport for advection, dispersion and chemical reaction of dissolved constituents in groundwater system on the transient condition. Leachate production rates are estimated by HELP(Hydraulical Evaluation of Landfill Performance) model and used weather records for recent 10 years. Leachate transport is predicted by a change of leachate level to after/before established HDPE, established slurry wall and wells.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.920-926
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• 2014

In this study, we applieorithmd the inverse analysis alg to the prediction of displacement shape in the example construction and verified the feasibility of suggested algorithm. For this purpose, as information processing knowledge in the field of IT is required and the need for convergence with the major is emerged, it is intended to try to apply the algorithm to the construction sector. Prediction of displacement shape is very important since it is related to the earth pressure of slurry wall and effecting on the safety of slurry wall after anchor removal. 3 levels of inverse analysis were applied to the slurry walls in 3 sites and compared the measured displacement shape with predicted displacement shape of the last excavation construction. As the predicted displacement shape was matched well with the measured one, the applied analysis algorithm in this study can be applied to the excavation construction.

• Journal of Powder Materials
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• v.21 no.1
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• pp.34-38
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• 2014

Cu-Ni alloys with unidirectionally aligned pores were prepared by freeze-drying process of CuO-NiO/camphene slurry. Camphene slurries with dispersion stability by the addition of oligomeric polyester were frozen at $-25^{\circ}C$, and pores in the frozen specimens were generated by sublimation of the camphene during drying in air. The green bodies were hydrogen-reduced at $300^{\circ}C$ and sintered at $850^{\circ}C$ for 1 h. X-ray diffraction analysis revealed that CuO-NiO composite powders were completely converted to Cu-Ni alloy without any reaction phases by hydrogen reduction. The sintered samples showed large and aligned parallel pores to the camphene growth direction, and small pores in the internal wall of large pores. The pore size and porosity decreased with increase in CuO-NiO content from 5 to 10 vol%. The change of pore characteristics was explained by the degree of powder rearrangement in slurry and the accumulation behavior of powders in the interdendritic spaces of solidified camphene.